Porthole black-out ventilator



J. S. TAYLOR PORI'HOLE BLACKOUT VENTILATOR Oct. 24, 1944.

Filed March 1, 1943 I 6 4th: may/J Patented Oct. 24, 1944 UNITED STATE-S PATENT OFFICE.

PQRTHOLE BLACK-OUT VENTILATOR John S. Taylor, Los Angeles, Calif; Application March 1, 1943; Serial No'-.- 477,598

7. Claims.

This invention relates to blackout ventilating structures for insertion in windows to pass air therethrough while preventing the passage of light and it is particularly applicable to round windows, such as the portholes of ships.

It is old toemploy blackout closures having crooked or tortuous air passages therethrough so as to eliminate any single straight paths from the interior to the exterior along which light might directly escape,- and to paint the surfaces black so that littleor no light could pass through by reflection. All such structures reduce the ventilating efficiency of the window, and this may not be important in some instances but it becomes seriousin thecase of portholes in ships because of their small size.- The ventilating elliciencies of the blackout closures previously applied to portholes have been poor because they produced abrupt changes in the direction of flow of air therethrough with consequent high flow resistance.

An object of the present invention is to provide a blackout closure for a circular opening that has a high ventilating efficiency:

Another object is to provide a simple and efficient blackout closure for' a porthole that provides for circulation of air in' both directions therethrough.

Another object is to provide a porthole blackout device of simple and rugged design that is economical to manufacture.

Essentially my porthole ventilating closure comprises a cylindrical casing adapted to extend through andfill aportholeand having'a helical bafile therein for'providing a helical passage of uniform curvature through which air can flow freely but through which light cannot pass.

Various novel details of construction will become apparent from the description to follow, which refers to the drawing.

In the drawing:

Fig. 1 is an elevation view of'a portion of a ships side showing a porthole equipped'with my ventilator.

Fig. 2 is a perspective view of the ventilator removed from the porthole.

Fig. 3 is a vertical section taken substantially in the plane IIIIII of Figure 1.

Fig. 41s a horizontal section'taken substantially in-the plane IV--IV of Figure 1.

Fig. 5 is an exploded view of the bafile elements of the device; and

Fig; 6 is a View of the blank from'which the bafile elements are'formed.

Referring to Fig. 2, the essentiafelements of" my ventilator consist of a cylindrical" casing 2!) containing a pair of bafile' elements 2l' and 22 positioned therewithin and defining an approximately helical air passage extending through the casing 2|];

The casing. 20 is positioned within the porthole opening and may extend to any desired extent on the inside or the outside of the ship. Ordinarily it is preferable to have the greater portion of the casing extending out of the ship since the device then consumes less space within the ship and exerts a more pronounced scooping efiec't' to catch air and direct it into the ship. The casing 20"m'ay be secured in place in any desired manner as by an annular flange 23 which may be secured to the casing by welding and may be secured against the edge of the porthole in any desired manner. As shown in Fig. 3, it is bolted to the wall 24 of the ship by bolts 25.

The two bafile elements 21 and 22,.which. deline the helical air passage through the casing 20; are identical and may be formed from the blank shown in Fig. 6. It will be observed that this blank includes a section I which is substantially a quadrant of a circle. A section 2 is approximately a quadrant of a circle, in which one bounding radius Bis common to the quadrant I. The other bounding radius 1 of section 2 is slightly longer than the radius 8 and it separates the quadrant 2'from a triangular section 3. The latter joins one diameter of a semicircular section 4" along one bounding radius IU of' the latter. The quadrants, I and Z'forming in efiect a semicircular partition member and a section 4 forming another semicircular partition member. The other bounding radius l l of section 4 merges into asecond triangular section 5.

Comparing Fig. 6 with Figs. 2 and 5, it will be observed that the blank is bent at an angle of approximately 30 along the line 8 and is bent at an angle of along the lines l, Ill and II, so that the triangular sections 3 and 5 lie in the same plane perpendicularly to the planes of the sections l, 2 and 4, but are positioned on the opposite sides of the section 4. .The element 22 is identical with the element 2| but is reversed so that the triangular section 5 of element 2! overlaps the triangular section 5a of element 221 After the elements 2| and 22 have been shaped.

as shown in Fig. 5, they fit snugly within the cylindrical casing 20 and are secured in position by welding along the lines of contact therewith.

It will be observed that the outer end of the casing 20 is cut flush with the surfaces of the of approximately helical shape through one revolution. The ends of this helical edge 21 are joined by a straight edge 26 extending substantially parallel to the axis of the cylinder. This edge 26, together with the edge 6, the edge 9 and the edge ll, define an entrance opening of approximately rectangular shape at right angles to the porthole opening. .It is usually desirable to so position the ventilator in the porthole that this entrance opening is facing forwardly so that the ships movement tends to force air into the opening. The inner end of the ventilating device is identical with the outer end so that the air leaves the ventilator substantially parallel to the wall of the ship instead ofbeing projected directly,

into the ship. From the foregoing it will be observed that the edges defined by the lines I I, I0, 6 and I lie in a common diametral plane so that the sections I, 2 and 4, when the baflie element is bent, lie transversely to a common longitudinal diametrical plane.

It will be observed that the triangular section 3 blocks movement of air into the ventilator below the level of the axis of the device and the double walled partition formed by the triangular sections 5 and 5a blocks circulating movement between the upper portions of the semicylindrical sections 4 and 4a, and likewise the triangular section 3a blocks out-flow of air below the axis of the casing. The use of these triangular sections as described promotes the fiow of air through the device in a helical path. They also provide important structural elements for stiffening the semicircular sections 4 and 4a and the quadrant sections 2 and 2a.

It is found that if air is directed into the opening in the outer end of the ventilator, as by forward movement of the ship, circulation of air both inwardly and outwardly through the ventilator can be had if the porthole communicates with a closed space within the ship. This makes possible the ventilation of a small cabin in which a single porthole constitutes the only exterior opening. The manner in which this two-way circulation occurs is shown in Fig. 3, in which the crosses 28 represent flow arrows at right angles to the plane of the drawing but going into the drawing and the dots 29 represent arrows perpendicular to the plane of the drawing but coming out of the drawing. It will be observed from these arrows 28 and 29 that the entering air by virtue of its velocity and resultant centrifugal force is thrown outwardly adjacent the surface of the cylinder 20, thereby permitting air from the interior of the ship to return through the ventilator adjacent the central axis thereof and be discharged from the lower portion of the outer opening. The reason for this separation of the inflowing and outflowing streams is that the infiowing air following the outer longer path has to travel faster than the outflowing air following the inner shorter path. By virtue of its greater velocity, the entering air is urged outwardly more strongly by centrifugal force than the leaving air. This circulation can be increased by providing an actual physical baflle dividing the helical passage into an inner and an outer portion, but surprisingly effective return ventilation results from the simple device as shown when it is installed in a porthole of a closed cabin. Of course, when the cabin has some other outlet for air, the entire passage in the ventilator will be filled with inflowing air.

It is not essential that the device be positioned with the openings above the axis. In fact the v proximately semi-circular device has the advantage of being self-draining if turned half a revolution from the position shown in the drawing, so that the openings are at the bottom. When the device is positioned as shown in the drawing, a drain hole may be provided in the bottom.

Various departures from the exact 'construction described can be made without departing from the invention, which is to be limited only to the extent set forth in the appended claims.

I claim:

1. A ventilator comprising a cylindrical casing and an approximately helical baffle means positioned coaxially within said casing and defining an approximately helical air flow passage therethrough, said baffie means including a plurality of approximately semicircular partition members all arranged transverse to a commonlongitudinal diametrical plane of said casing and having their diametrical edges in said common diametrical plane and their peripheral edges contacting said cylindrical casing, successive ones of said members being on opposite sides of said diametrical plane and inclined so as to approach each other at one end of said diametrical edges.

2. A ventilator as described in claim 1, in which the baflie means includes longitudinal partitions interconnecting each successive pair of said appartition members along portions of their diametrical edges, said longitudinal partitions extending inwardly from the diametrical ends of the approximately semicircular partition members with which they are associated.

3. A ventilator as described in claim 1, in which two adjacent transverse partition members consist of a single blank of sheet material, said blank comprising a pair of approximately semi-circular sections interconnected along portions of their longitudinal diametrical edges by a triangular section, said blank being bent in opposite directions at right angles along the two junction lines between said triangular section and said two semicircular sections.

4. A ventilator as described in claim 1, in which two adjacent semicircular partition members each have integral triangular members extending at right angles fro-m portions of their respective diametrical edges into overlapping relation with each other.

5. A ventilator comprising: a cylindrical casing and an approximately helical baffle means positioned coaxially within said casing and defining an approximately helical airflow passage therethrough, said bafile means having a radial width substantially equal to the radius of the internal diameter of said casing, whereby there is no straight passageway through said casing for the passage of light from one end to the other thereof, said helical bafile means having substantially one complete convolution thereof exposed and arranged to form a transversely extending closure for one end of said casing, said one end of said casing being contoured to coincide with the helix defined by the periphery of said one exposed convolution of said bafiie means.

6. A ventilator as described in claim 5, in which the exposed convolution of said helical baffle means includes longitudinally spaced ends and said cylindrical casing includes a longitudinal edge portion between said ends of said convolution, whereby to provide an opening for said helical passage lying in a longitudinal diametrical plane approximately common to the axis of said cylindrical casing.

ing a, longitudinal edge portionbetween the outer ends of said radial edges cooperating with said radial edges and said edge of said longitudinal partition to provide an opening for said helical passage lying in a longitudinal diametrical plane approximately passing through the axis of said cylindrical casing.

JOHN S. TAYLOR. 

